I'll suggest something different.
Divine casters have a much, much easier time doing a number with necromancy than (most) arcane casters: they get Rebuke Undead, they get Desecrate, they get to use an Inflict Light Wounds wand or cast Harm, later on. Dread Necromancers can do these things (not Desecrate unless you fiddle around a bit), but they're straight up worse for versatility.
Swashbucklers are basically just tricky, flashy warrior types. No need to use the class of the same name, which incidentally doesn't really allow you to do cool, flashy things anyway. But what class does? Initiators do, and Swordsages are the swashiest of those.
Now it's time to mix and match:
Swordsage 2/Cleric 2/Crusader 1/Ruby Knight Vindicator 10/[full divine caster] 5.
Focusing RKV on Swordsage maneuver progression, you get all kinds of neat, swashbuckler-y stuff to do in combat, BAB 16 (full BAB with Divine Power, of course), and 8th level divine spells, with some nice Wis synergy tacked on for good measure. Practiced Spellcaster bumps your CL up to 20. Corpsecrafter feat line makes your undead minions powerful. White Raven maneuvers can be cherrypicked to help your pale buddies in combat, while not detracting from your own actions. Mix RKV levels with [full divine caster] levels to get the maneuvers you want at the levels you want. Burn turn/rebuke undead uses to fuel swift actions and get your most-beloved maneuvers back, nullifying the Swordsage's weak points. All in all, quite a measure of goodness, if not totally optimized.
See? You don't have to suck moose testicles with three levels of Swashbuckler, just to 'build to a concept'.